Retraction status of “Glaciar Norte” of Pico de Orizaba, Mexico: Update to 2024

Abstract

Given that the “Glaciar Norte” of Pico de Orizaba is one of the last glaciers in Mexico and the only ones located at 19° north latitude in the world, it is crucial to observe its retreat and eventual disappearance to document its spatio-temporal evolution and to identify the factors that drive these changes. We update here the glacier ice areal extent up to May 2024, resulting an area of 0.37 km² and a glacier front altitude of 5130 m asl. The air temperature at the lower part of the ice body and within its accumulation zone has increased steadily, whilst precipitation has decreased during the months when solid precipitation commonly occurs in the country. Furthermore, since 2019, portions of the bedrock in the accumulation zone of the glacier have been exposed to solar radiation, resulting in the accumulation of energy. The temperature values obtained on the bare rock surface indicate that, from a thermodynamic perspective, the stored energy is causing the melting of the adjacent ice and snow through due to heat emission. This leads to the conclusion that, in addition to the retreat of the glacier front, ice melting is also occurring in what should be the solid precipitation accumulation area, resulting in an overall more pronounced retreat. The results obtained complement and update the monitoring work that has been carried out before, while also maintaining surveillance for the duration of the glacier's remaining lifespan.